The present invention relates generally to an erosion resistant wear sleeve at the fluid outlet of a pressure valve. More particularly, to a wear sleeve having a diverging fluid outlet end for transitioning from the smaller choke passage to the larger line bore.
High-pressure valves for controlling flow of drilling fluids are important devices in the exploration and production of oil and gas. In the trade such valves are commonly referred to as choke valves.
A choke valve is exposed to erosive and corrosive drilling fluids for extended periods of time. Drilling fluids are designed to carry the debris from the drill bit to the surface and often are quite viscous and particle-laden. The choke valve is subjected to high flow velocities of these dense, particle-laden fluids creating an extremely erosive environment.
When a pay-zone is reached, pressures immediately increase, forcing the drilling fluids to the surface in the return line. Generally when this occurs, the blowout preventers are closed and the pressure is controlled through the choke valves. When the choke valve is closed, it should seat tightly so that no leakage occurs. For this reason erosion of the valve seat and/or the gate can be a severe problem.
However, deterioration of any component within the choke valve is a problem that requires the system to be shut down and the eroded component to be replaced. Another component of the choke valve that experiences rapid erosion is the extreme end of the fluid outlet where the choke valve joins the pipeline. The accelerated erosion of the fluid outlet end is associated with a flow discontinuity caused by the abrupt transition from the smaller choke passage to the larger line bore. A need exists for a mechanism for minimizing this erosion to prolong the useful life of the choke valve.
The present invention provides a wear sleeve and a replaceable retainer ring, wherein the outlet end of the retainer ring is altered to decrease the abruptness of the transition from the smaller choke passage to the larger line bore. The outlet end may be tapered, curved or otherwise shaped so that the internal diameter of the retainer ring increases at its outlet end.
The foregoing has outlined rather broadly several aspects of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention.
It should be appreciated by those skilled in the art that the conception and the specific embodiment disclosed may be readily utilized as a basis for modifying or designing other tools for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.